Light emitting diodes (LED) which are semiconductor light-emitting elements are smaller, have higher efficiency and longer product life than the conventional illumination light sources. Recent market needs for saving energy and resource boost the demand for light bulb shaped lamps using LEDs (hereafter simply referred to as “LED light bulb”) and lighting apparatuses including the LED light bulbs, replacing conventional incandescent light bulbs using filament coils.
Known properties of LEDs include reduced light output as temperature increases, which lead to shorter product life. In response to this problem, a metal case is provided between semispherical globe and a base in a conventional LED light bulb so as to suppress the increase in the temperature of LED (for example, see Patent Literature 1). The metal case functions as a heat sink for radiating heat generated in LED to outside, making it possible to suppress the increase in the temperature of LED and to prevent the reduction in light output.